An
old thread discusses the pros and cons of this formation vs that one. Do keep in mind though that there's been some significant errata and clarifications that affect many of the thoughts expressed in the thread.
To update my positions expressed in that old thread:
Battle Lance: Still the gold standard, even at a cap of 1 reroll per turn. The fungible nature of those rerolls across the units of the lance is still borderline broken-good.
Striker Lance: +2" of movement is very, very good (even when it's not modifying TMM). Particularly in hexless play, where you can nudge *just out* of this or that guy's firing arc.
Fire Lance: Still good, but a bit indirectly nerfed by the Scout lance getting nerfed. Still, they're good enough I'd probably still more likely than not take one in a company where I only get to pick 3 kinds of lances.
Scout Lance: They're ok, which is a far fall from "broken good".
Pursuit: Went from hot garbage to viable via the errata that allows their Blood Stalker "virtual SPAs" to apply to a whole target formation, rather than a specific unit.
Assault: Went from hot garbage to viable via the errata and clarifications to Demoralizer (i.e. it gets high TMM units killed dead)
Command: Meh. I'd place it least good of the lot, but because nothing SUCKS now instead of Command being terrible in of itself.
And since then there's been some new lance types available in the abortive CM series:
Demi-Company: Hot garbage *if* you're not using the FP building system *and* you're representing a unit that used Demi-companies. Pretty much just exists to not punish you for sticking to canon with the Black Thorns if you're using FPs. So yeah, still kind of not broadly appealing.
Security Lance: more intrigued by the possibilities here than with Command Lance, but that's my personal preference
Horde Lance: Try it out for the lolz, keep playing it for the board control it brings by switching who your opponent is shooting at.
Order Lance: Kurita specific, but if you don't mind embracing your inner Drac this is a neat way to represent the discipline and skill of Bushido-obsessed mechwarriors. (AS always needed something like a Kurita version of Zell)
Berserker Lance: Play it for the lolz. Why not give it a shot if you have 2 (exactly 2) MEL mechs in your list?
Anti-Mech Lance: Finally, something to do with Infantry besides designating them a Support Lance.